Dr. Aun Pyae Phyo, who leads the Whampa malaria clinic on the Thailand-Burma border, says the number of malaria cases has dropped considerably over the past five years, but the remaining ones are harder to treat.

One place where this resistance was first found is along the border between Thailand and Myanmar, also known as Burma.

At the small Whampa health clinic on the Thai side of the Moi River, Dr. Aun Pyae Phyo is treating a 5-year-old Burmese boy with severe malaria. The boy had been carried to the clinic three days earlier.

"On that day, he couldn't even move his limbs," the doctor says of the boy. "So we need to start intravenous anti-malarial drugs, and we also need to transfuse him with blood."

If the boy's mother had waited even a day longer to come to the clinic, the doctor says, the child probably would have died. But the boy responded well to an initial dose of intravenous artemisinin drugs. The staff followed that with a three-day regimen of pills including artemisinin.

This is what these drugs have done so well around the world — a child is on the verge of death, and a quick course of artemisinin brings him back to health.

But over the past couple of years, doctors have started to see that some cases of malaria don't respond in the same way to these powerful anti-malarial medications.

"If the parasite strain inside that kid turned out to be resistant," Dr. Aun Pyae Phyo says shaking his head, "the scenario would turn out to be quite disastrous."

He says the boy's first day at the clinic was critical. If the parasite hadn't responded to the initial treatment and had continued to multiply in the boy's body, the infection could have been fatal.

So far, the cracks in artemisinin's armor are minor. Sometimes the drugs just take longer to work. But it's clear that the malaria parasite is evolving, shifting, learning how to outwit the drugs that were designed to kill it.

Francois Nosten, the head of the Shoklo Malaria Research Unit, which runs this clinic on the Thai-Burma border, says drug-resistant malaria is still the exception rather than the rule here, but it's a major concern.

"Clearly it's very worrying," Nosten says. "These drugs have been very effective."

If artemisinins aren't part of the medical staff's arsenal at this clinic, there are few other options.

Malaria has developed resistance to most of the other major drugs thrown at it. Chloroquine and Fansidar, which were once leading malaria treatments, are now useless against the parasite in many parts of the world. The expectation among researchers is that this will also happen eventually with artemisinins.

Some new drugs are being developed, but they probably won't be available for at least five years.

Nosten says public health officials should use this moment, while artemisinins are still mostly effective, to launch an all-out "war" against malaria. "We are in a race," he says. "Either we eliminate malaria, or if we don't, then we think the parasite will become more and more resistant, and we won't be able to use these drugs any more ... And we'll have almost no drug to treat it."

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

Transcript

RENEE MONTAGNE, HOST:

The fight against malaria is becoming more pressing in Southeast Asia. Thailand, for one, has greatly reduced malaria infections through various control measures, including better drugs to treat it. But along Thailand's borders, new strains of malaria are emerging that are resistant to the most effective drugs. As NPR's Jason Beaubien reports from Thailand, the rise of these new forms of malaria could reverse years of progress.

JASON BEAUBIEN, BYLINE: The Whampa clinic sits on the eastern bank of the Moi River, on the border between Thailand and Myanmar, also known as Burma. Each morning, dozens of Burmese cross the muddy, cafe-cream-colored river in narrow skiffs; to seek medical attention at the simple health facility. And the first thing the clinic staff does, is to test anyone with fever for malaria.

DR. AUN PYAE PHYO: Five or six years ago, 90 percent of the patients had malaria. But these days, only 10 percent have malaria; and 90 percent are other kinds of infection.

BEAUBIEN: Dr. Aun Pyae Phyo, the lead doctor at the clinic, says malaria remains a major health problem in the area, particularly on the Burmese side of the border. And the cases they're seeing here, at his clinic, are growing harder to treat. On this morning, the doctors are tending to a 5-year-old malaria patient who had been carried into the clinic three days earlier.

AUN PYAE PHYO: On that day, he couldn't even move his limbs, so we need to start the intravenous, anti-malaria drops. And we also need to transfuse him with blood.

BEAUBIEN: The boy had traveled for more than half a day, with his mother, from deep inside Burma, to reach the clinic. By the time he arrived, he was suffering from severe malaria. Dr. Aun Pyae Phyo says if the mother had waited even a day longer to bring her son to the clinic, the child probably would have died. The boy responded well to an initial dose of intravenous, artemisinin drugs. The staff followed that with a three-day regimen of pills, including artemisinin. The problem is that lately here, doctors have been finding that some forms of the malaria parasite are growing resistant to artemisinin.

AUN PYAE PHYO: If the parasite strain in that kid turned out to be resistant, the scenario would be quite disastrous.

BEAUBIEN: The first day at the clinic, for this boy, was critical, Dr. Aun Pyae Phyo says. And if the parasite had continued to multiply in his body, the infection could have been fatal. This clinic is run by the Shoklo Malaria Research Unit, or SMRU, which is a part of Mahidol University. Francois Nosten, the head of SMRU, says drug-resistant malaria is still rare here, but it's a major concern.

(SOUNDBITE OF BIRDS CHIRPING)

BEAUBIEN: Sitting behind the clinic with chickens marching past his feet, Nosten said artemisinins are the last best drugs currently available, to treat malaria. And the threat of losing them should push the global community to launch an all-out war against the disease.

FRANCOIS NOSTEN: Either we eliminate malaria - or if we don't, then we think that the parasite will become more and more resistant; to such an extent, and such a point, that we won't be able to use these drugs anymore. So we would have lost that race, and then we'd know what's going to happen next. Malaria would be on the rise, and we have almost no drug to treat it.

BEAUBIEN: Drug resistance among malaria parasites is currently being seen here, along Thailand's western border; and also along Thailand's eastern border, with Cambodia. This part of the world is also where resistance first emerged to Chloroquine, one of the most famous - and effective - anti-malaria drugs of the 20th century. Chloroquine started to fail here in the 1960s, and then that resistance spread to the rest of the globe.